Film-covered terminal

ABSTRACT

A film-covered terminal comprises a foil-like or plate-like electrode terminal with its opposite surfaces covered with sealing films through bonding layers respectively, a rivet of a conductive plastic material inserted through the electrode terminal, the bonding layers, and the sealing films, and welded to the electrode terminal, the bonding layers, and the sealing films, and a soldering member secured to an end portion of the rivet. A method of manufacturing a film-covered terminal is also disclosed which comprises the steps of covering opposite surfaces of a foil-like and plate-like electrode terminal with sealing films through bonding layers respectively, inserting a rivet of an electrically conductive plastic material into a through hole formed through the electrode terminal, the bonding layers, and the sealing films, the rivet having an end portion at which a soldering member is secured, and thermally press-bonding the opposite ends of the rivet.

This is a divisional application based on copending application Ser. No.756,328, filed July 18, 1985, now U.S. Pat. No. 4,653,186.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a film-covered terminal andmore particularly to a film-covered terminal in which a foil orplate-like electrode terminal is sealed with sealing films.

2. Description of the Prior Art

Referring to FIG. 2(a) of the drawings, in the conventional film-coveredterminal, the opposite surfaces of a foil or plate-like electrodeterminal 11 are respectively covered with sealing films 13 and 13' eachcomposed of polyester, or the like, through bonding layers 12 and 12'each composed of a thermoplastic resin material, such as polyethylene,or the like. In this case, an end portion of the electrode terminal 11is extended outward from the sealing films 13 and 13' so that it can besoldered to an external circuit. In manufacturing such a film-coveredterminal, the bonding layers 12 and 12' are laminated in advance on therespective surfaces of the sealing films 13 and 13', the electrodeterminal 11 is sandwiched between the sealing films 13 and 13' with therespective bonding layers 12 and 12' disposed inside, and then thesealing films 13 and 13' are pressed against the electrode terminal 11at about 120° C. whereby the bonding layers 12 and 12' are melted so asto perform bonding seal between the electrode terminal 11 and each ofthe sealing films 13 and 13'.

As shown in FIG. 2(b), however, there have been disadvantages in theconventional film-covered terminal that the sealing films 13 and 13' areapt to be separated from the electrode terminal 11 together with thebonding layers 12 and 12' and moisture is apt to enter the boundarysurfaces a and a' between the electrode terminal 11 and the respectivebonding layers 12 and 12', or the like.

To improve the above-mentioned disadvantage, a film-covered terminal inwhich a hot-melting agent of proper adhesion is coated over therespective surfaces of the electrode terminal 11 and the bonding layers12 and 12' at the boundary surfaces a and a' has been tried. Even inthis case, however, there is a further disadvantage that if externalforce is exerted onto a portion of the terminal, the adhesion of thebonding layers 12 and 2' is deteriorated, so that moisture mayoccasionally enter gaps between the electrode terminal 11 and thebonding layers 12 and 12'.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a film-covered terminalin which sealing films and bonding layers are not apt to be separatedfrom an electrode terminal and moisture is prevented from entering thefilm-covered terminal.

According to one aspect of the present invention, the film-coveredterminal comprises a foil-like or plate-like electrode terminal with itsopposite surfaces covered with sealing films through bonding layersrespectively, a rivet of a conductive plastic material inserted throughthe electrode terminal, the bonding layers, and the sealing films, andwelded to the electrode terminal, the bonding layers, and the sealingfilms, and a soldering member secured to an end portion of the rivet.

Therefore, according to the present invention, the electrode terminal isentirely embedded in the sealing films and the electrode terminal iselectrically connected to an external circuit through a conductiverivet, so that the adhesion of a sealing portion becomes securer andmoisture can be prevented from entering the structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a) to 1(f) are diagrams illustrating an embodiment of thepresent invention, in which:

FIG. 1(a) is a sectional view showing the state in which an electrodeterminal is covered with bonding layers and sealing films;

FIG. 1(b) is a plan view of the same;

FIG. 1(c) is a sectional view of a rivet;

FIG. 1(d) is a sectional view showing the state in which the rivet isinserted through and thermally press-bonded;

FIG. 1(e) is a sectional view of the film-covered terminal which hasbeen manufactured;

FIG. 1(f) is a sectional view showing the state in which an externalterminal is soldered;

FIGS. 2(a) and 2(b) are diagrams showing a conventional film-coveredterminal, in which:

FIG. 2(a) is a sectional view of the same; and

FIG. 2(b) is a sectional view showing the state in which bonding layersand sealing films are separated from an electrode terminal.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, an embodiment of the present invention willbe described hereunder.

As shown in FIGS. 1(a) and 1(b), the opposite surfaces of an electrodeterminal 21 are covered with sealing films 23 and 23' through bondinglayers 22 and 22', respectively. That is, the bonding layers 22 and 22'formed in the form of film have been laminated in advance on therespective surfaces of the sealing films 23 and 23', the electrodeterminal 21 is sandwiched between the sealing films 23 and 23' with thebonding layers 22 and 22' inside, and then the sealing films 23 and 23'are thermopressed against the electrode terminal 21 whereby the bondinglayers 22 and 22' are melted so as to form a bonded seal between theelectrode terminal 21 and each of the sealing films 23 and 23'. In thiscase, through holes have been respectively formed through the electrodeterminal 21, the bonding layers 22 and 22', and the sealing films 23 and23'; and in bonding the layers, the through holes are registered toconstitute a through hole 24.

The diameter of the through hole formed in the electrode terminal 21 ismade slightly smaller than that of each of the other through holes sothat that the through hole 24 is narrowed at its intermediate portion24_(a).

For example, a metal foil or plate of copper, or the like, may be usedas a material for the electrode terminal 21. Alternatively, as amaterial for the electrode terminal 21, it is possible to use anelectrically conductive resin sheet or film in which electricallyconductive powder, such as carbon powder, silver powder, nickel powder,copper powder, or the like, is mixed with a thermo-setting resinmaterial of such as epoxide group, phenol group, polyester group, or thelike, or a thermoplastic resin material, such as polyethylene,polystyrene, polyamide, polyvinyl alcohol, polypropylene, or the like. Athermoplastic resin material, such as polyethylene, or the like, is usedas a material for the bonding layers 22 and 22'. A film having a lowcoefficient of water absorption, such as polyester, trifluoroethylene,polyvinyl chloride, polyvinylidene chloride, polycarbonate, or the like,is used for the sealing films 23 and 23'.

An electrically conductive rivet 25 as shown in FIG. 1(c) is insertedthrough the through hole 24. A material in which an electricallyconductive powder, such as carbon powder, silver powder, nickel powder,copper powder, or the like, is mixed with a resin material, such aspolyethylene, polystyrene, epoxide resin, polyvinyl chloride, or thelike, may be used for the rivet 25. A soldering member 26 constituted bya metal plate such as a copper plate plated with tin, or the like, isattached on the head portion of the rivet 25.

As shown in FIG. 1(d), the rivet 25 is heated and pressed, as shown byarrows P and P', from upper and lower sides thereof by thermal presses27 and 27'. Thus, the rivet 25 is melted, and adhesively closely bondedto the electrode terminal 21, the bonding layers 22 and 22', and thesealing films 23 and 23', at the inside peripheral portions of and theperiphery of the opening portions of the through hole 24. The thusbonded state is shown in FIG. 1(e). Accordingly, the electrode terminal21 is entirely embedded in the bonding layers 22 and 22' and the sealingfilms 23 and 23', and the electrode terminal 21 is adapted to beelectrically connected to an external circuit through the rivet 25.

As shown in FIG. 1(f), an external terminal 28 is soldered to thesoldering member 26 through a soldering layer 29. Thus, the electrodeterminal 21 is electrically connected to the external terminal 28through the rivet 25, the soldering member 26, and the soldering layer29.

Further, in the state as shown in FIGS. 1(a) and (b), if the peripheryof the opening portions of the through hole 24 and the rivet areirradiated with ultraviolet rays so as to activate the molecules of thesealing films 23 and 23', the adhesion can be improved when the rivet 25is inserted and thermo-pressed, resulting in improvement inair-tightness.

Embodiment 1:

A film-covered terminal was produced by using a copper foil as amaterial for an electrode terminal 21, a polyethylene film of athickness of about 0.06-0.1 mm for bonding layers 22 and 22', and apolyester film of a thickness of about 0.2-0.5 mm for sealing films 23and 23'. The bonding layers 22 and 22' had been laminated in advance onthe sealing films 23 and 23', respectively, and then a through holehaving a diameter of 3 mm had been also formed in each of the laminatedlayers 23, 22 and 23', 22'. A through hole having a diameter of 2 mm hadbeen formed in advance in the electrode terminal 21. The electrodeterminal 21 was sandwiched between the sealing films 23 and 23' with thebonding layers 22 and 22' laminated thereon respectively, and all thelayers where thermally press-bonded to form an integral assembly. Atthis time, the through hole formed in the electrode terminal 21 and therespective through holes formed in bonding layers 22 and 22' and thesealing films 23 and 23' were registered to each other to form a generalthrough hole 24. A mixture of polyethylene and carbon powder was used asa material for a rivet 25 and a soldering member 26 composed of a copperplate plated with tin was secured to the head portion of the rivet 25.Then the rivet 25 was inserted through the through hole 24 and the rivet25 was thermally press-bonded from its opposite ends at 120°-150° C. forfive minutes by thermal presses 27 and 27', so that the rivet 25 wasmelted and bonded to the assembled layers. In the thus manufacturedfilm-covered terminal, both the rivet 25 and the bonding layers 22 and22' were composed of the same material (that is polyethylene) so thatthey were melted and mixed together to obtain proper adhesion. As aresult, a film-covered terminal could be obtained in which the sealingfilms 23 and 23' were not apt to be separated from the electrodeterminal 21 and which had a proper property of air-tightness.

Embodiment 2:

A film-covered terminal was manufactured in the same manner as in theEmbodiment 1 except that ultraviolet rays were irradiated onto theperiphery of opening portions of the through hole 24 when the rivet wasinserted into the through hole 24. In this film-covered terminal, theadhesion between the rivet 25 and the sealing films 23 and 23' was madesecurer.

Embodiment 3:

A film-covered terminal was manufactured in the same manner as in theEmbodiment 1 except that a mixture of an epoxide resin material andcarbon powder was used as a material for the rivet 25 and thermallypress-bonding was made under the condition of 120°-150° C. for twentyminutes. As a result, a film-covered terminal having a property ofproper adhesion could be obtained.

Embodiment 4:

A film-covered terminal was manufactured in the same manner as in theEmbodiment 1 except that a mixture of polyvinyl chloride and carbonpowder was used as a material for the rivet 25 and thermallypress-bonding was performed under the condition of 100°-160° C. for fiveminutes. As a result, a film-covered terminal having a property ofproper adhesion could be obtained.

Embodiment 5:

A film-covered terminal was manufactured in the the same manner as inthe Embodiment 1 except that a mixture of polyvinylidene chloride andcarbon powder was used as a material for the rivet 25 and thermallypress-bonding was effected under the condition of 130°-150° C. for fiveminutes. As a result, a film-covered terminal having a property ofproper adhesion could be obtained.

Embodiment 6:

A film-covered terminal was manufactured by the same method as in theEmbodiment 1 except that a conductive plastic sheet composed of amixture of epoxide resin and carbon powder was used as a material forthe electrode terminal 21. As a result, there was a film-coveredterminal having a property of proper adhesion among the respectivelayers.

Embodiment 7:

A film-covered terminal was manufactured by the same method as in theEmbodiment 1 except that a conductive plastic sheet composed of amixture of polyethylene and carbon powder was used as a material for theelectrode terminal 21. As a result, there was a film-covered terminalhaving a property of proper adhesion among the respective layers.

Embodiment 8:

A film-covered terminal was manufactured in the same manner as in theEmbodiment 1, except that a trifluoroethylene resin material was used asa material for the sealing films 23 and 23'. As a result, there eas afilm-covered terminal having a property of proper adhesion among therespective layers.

As described above, according to the present invention, an electrodeterminal is entirely embedded in bonding layers and sealing films, andthe electrode terminal is electrically conducted to an external circuitthrough a rivet, resulting in adhesion as well as airtightness betweenthe respective layers to thereby obtain a film-covered terminal in whichthe bonding layers and the sealing films are not apt to be separatedfrom the electrode terminal and moisture can hardly enter thefilm-covered terminal.

What is claimed is:
 1. A film-covered terminal comprising:an electricterminal having opposite surfaces thereof covered with sealing filmsapplied through bonding layers, respectively; a rivet of an electricallyconductive plastic material inserted into a through hole formed throughsaid electric terminal, said bonding layers, and said sealing films; theopposite ends of said rivet being thermally press-bonded such that theelectrically conductive material thereof is thermally melted andsecurely bonded physically and electrically together with said bondinglayers, said sealing films, and said electric terminal; and a solderingmember secured to one of said press-bonded ends of said rivet.
 2. Afilm-covered terminal according to claim 1, in which the material ofsaid bonding layers and that of said rivet contain a common material toeach other.
 3. A film-covered terminal according to claim 2, in whichsaid common material is polyethylene.